User Local machine Identity

Is it possible to get a User's Local machine identity?
If I want to dig out which user has access my online application, I need to grab his/her machine's identity (I dont want ISP's address which is there in $_SERVER['REMOTE_ADDR']). An ISP can be shared by many users. I want to fine tune to specific user who accessed my application.

Let me give some more insight.
I am creating a hotel booking service website. I want to capture as much info as possible about the user and his machine. If he messes around with the booking system (involving payment system also) then I might blacklist him.
A user can be identified by login id /password but only when he/she is logged in.
I have an option of allowing somebody using this service(hotel booking etc) with even logging in ie as anonymous. In this there would be possibilities of hack attempts and all. Here, I want to capture user's machine's identity.

I think you are thinking too much. Payment systems hacking can be prevented by the payment processing system only and if you want to black list cookies+ip is your best choice if you allow anonymous buying of your product

cookie + ip is the way to go I dont think php can get the remote machines name. You may want to do a check to see if the ip is a proxy then a conversion to change it back to its original IP then black list that. It would only black list those who use that IP not anyone from that ISP, ISP is the service provider of your net and your ip is your unique ID for your connection while on the net.